ASCII PERIODIC TABLE OF THE ELEMENTS

  Pm

Relative atomic mass: [145]

English: Promethium
French: Promethium
Croatian: Prometij
German: Promethium
Italian: Promezio
Spanish: Prometio

Atomic number: 61
Group numbers: 3
Period: 6
Standard state (20 oC): solid

Discovery: 1947 Jacob Akiba Marinsky, Lawrence Elgin Glendenin, Charles DuBois Coryell (US)
Promethium was discovered by Jacob Akiba Marinsky, Lawrence Elgin Glendenin, and Charles DuBois Coryell (US) in 1947. Named after Prometheus in Greek mythology, who stole fire from the gods. It is a rare earth metal of synthetic origin on the earth, naturally made in stars. It is Poisonous, radiotoxic and radioactive. Promethium does not occur naturally. It is found among fission products of uranium, thorium and plutonium. It has been used as a source of radioactivity for thickness-measuring gages.
Electronic configuration: [Xe] 4f5 6s2
Formal oxidation number: +3
Atomic radius: 183.4 pm

Electronegativities: -
Thermal conductivity: 17.9 W/(m K)
Electrical resistivity (20 oC): - microOhm cm

Melting point: 1042 oC
Boiling point: 3000 oC

Heat of fusion: 12.6 kJ/mol
Heat of vaporization: - kJ/mol
Heat of atomization: 308 kJ/mol

60Nd <= 61Pm => 62Sm


ASCII Periodic Table of the Elements
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29 Aug. 2017
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